Add a map of Nextstrain clade to Pango lineage

Adds an official map between Nextstrain clade and Nextclade pango
lineage to support analyses that need to convert between these two
lineage naming systems.

defaults/Nextstrain_clade_Pango_lineage.tsv

@@ -0,0 +1,23 @@
+Nextstrain_clade	Nextclade_pango
+22A	BA.4
+22B	BA.5
+22C	BA.2.12.1
+22D	BA.2.75
+22E	BQ.1
+22F	XBB
+23A	XBB.1.5
+23B	XBB.1.16
+23C	CH.1.1
+23D	XBB.1.9
+23E	XBB.2.3
+23F	EG.5.1
+23G	XBB.1.5.70
+23H	HK.3
+23I	BA.2.86
+24A	JN.1
+24B	JN.1.11.1
+24C	KP.3
+24D	XDV.1
+24E	KP.3.1.1
+24F	XEC
+24G	KP.2.3